1. Field of the Invention
The present invention relates to an automatic steering system for a vehicle for garaging the vehicle without recourse to a steering by a driver.
2. Description of the Prior Art
Such automatic steering systems for vehicles are already known from Japanese Patent Application Laid-open No. 3-74256 and 4-55168. The automatic steering systems for vehicles utilize an actuator for a conventionally well-known power steering device, and are designed so that back parking and linear parking are automatically controlled by controlling the actuator based on the relationship between a previously stored distance of movement of the vehicle and a steering angle. There is also an automatic steering system which is already known from Japanese Patent Application Laid-open No. 62-278477 and which is designed, so that a warning is provided if an obstacle is detected within a presumed locus of movement of the subject vehicle during a parking operation provided by a driver.
If a warning device for emitting a warning by detecting an obstacle is combined with the automatic steering system for the vehicle, it is possible to further reliably carry out the automatic parking. In the warning device described in Japanese Patent Application Laid-open No. 62-278477, however, the warning is emitted immediately before contact of the vehicle with the object and hence, there is a possibility that the operation for keeping the vehicle from contacting the obstacle is not in time. In addition, if the warning is emitted during automatic parking, the parking operation is conducted again from the beginning, resulting in a troublesome operation.
The above known automatic steering system also suffers from the problem that the vehicle is moved from a start position through a previously stored locus of movement to a parking position and hence, if the start position is deviated, the parking position is also deviated. Additionally, the surrounding situation around the parking position (for example, the positions of other vehicles parked on left and right opposite sides and the like) is not taken into consideration and hence, a final parking position may deviate in some cases from an appropriate parking position depending upon the surrounding situation.
Accordingly, it is an object of the present invention to ensure that when there is one or more obstacles existing within a presumed locus of movement of a vehicle to be parked, or when the start position at which the automatic parking control is started has been deviated, automatic parking control can be reliably performed.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided an automatic steering system for a vehicle, comprising a steering actuator for steering the wheels based on the steering operation provided by a driver, a memory means for previously storing the locus of movement of the vehicle to a target position, a control means for controlling the steering actuator based on contents stored in the memory means in place of the steering operation by the driver, and an object detecting means for detecting an object near the vehicle. The automatic steering system further includes a determining means for determining the presence or absence of an object or obstacle which exists within the locus of movement, or which will become an obstacle in the locus of movement, based on an output from the object detecting means, during the controlling of the steering actuator based on the contents stored in the memory means.
With the above arrangement, a contact avoiding measure can be taken to prevent the vehicle from contacting with the obstacle during the automatic parking control. Moreover, when there is an obstacle already existing within the locus of movement of the subject vehicle at the start of the automatic parking control, the need for a wasteful execution of the automatic parking control is eliminated, leading to a saving of time.
According to a second aspect and feature of the present invention, in addition to the first feature, the memory means stores the locus of movement of the vehicle as a steering angle of the wheel with respect to a distance of movement of the vehicle.
With the second feature, the constant locus of movement can be ensured irrespective of the magnitude of the vehicle speed during the automatic parking control.
According to a third aspect and feature of the present invention, in addition to the first or second feature, the automatic steering system further includes a notifying means for notifying a driver of the presence of an object, when the determining device determines that there is an object which becomes an obstacle.
With the third feature, it is possible to urge the driver to conduct an operation for keeping the vehicle from contacting the obstacle.
According to a fourth aspect and feature of the present invention, in addition to the first or second feature, the automatic steering system further includes an automatic vehicle-stopping means for automatically stopping the vehicle when the determining means determines that there is an object which becomes an obstacle.
With the fourth feature, it is possible to automatically avoid the contact of the vehicle with an object which becomes an obstacle.
According to a fifth aspect and feature of the present invention, in addition to the fourth feature, the vehicle includes an automatic transmission, and the operation of the automatic vehicle-stopping means is canceled by the operation of a brake input means by the driver, or by shifting the automatic transmission into a parking position.
With the fifth feature, it is possible to prevent the vehicle from starting to be moved at the time when the operation of the automatic vehicle-stopping means is canceled.
According to a sixth aspect and feature of the present invention, in addition to any of the first to fifth features, the steered wheels are front and rear wheels.
With the sixth feature, the vehicle is capable of a small sharp turn and hence, can be easily parked in a narrow area.
According to a seventh aspect and feature of the present invention, in addition to the first feature, the automatic steering system further includes a correcting means for correcting the contents stored in the memory means, when the determining means determines that there is an object which becomes an obstacle.
With the seventh feature, the locus of movement of the vehicle can be corrected in accordance with the deviation of the start position of the automatic parking control and with the situation of a surrounding obstacle around the parking position, whereby the vehicle can be reliably parked at an appropriate position.
According to an eighth aspect and feature of the present invention, in addition to the seventh feature, the correcting means corrects the relationship of the steering angle of the wheels to the distance of movement of the vehicle stored in the memory means.
With the eighth feature, it is possible to easily and reliably perform the correction of the locus of movement of the vehicle.
According to a ninth aspect and feature of the present invention, in addition to the seventh feature, the steered wheels are front and rear wheels, and the memory means stores a first locus of movement when one of the front and rear wheels is steered, and a second locus of movement when both of the front and rear wheels are steered.
With the ninth feature, it is possible to properly use the automatic parking control in a two-wheel steered state and the automatic parking control in a four-wheel steered state depending upon the deviation of the start position at which the automatic parking control is started, and the situation around the parking position.
According to a tenth aspect and feature of the present invention, in addition to the ninth feature, the first or second locus of movement is selected based on the result of the determination in the determining means.
With the tenth feature, it is possible to properly use the automatic parking control in the two-wheel steered state and the automatic parking control in the four-wheel steered state depending upon the deviation of the start position at which the automatic parking control is started, and the situation around the parking position, which is determined by the determining means.